This relates generally to electronic devices and, more particularly, to electronic devices with displays and associated backlight structures.
Electronic devices such as computers and cellular telephones have displays. Some displays such as plasma displays and organic light-emitting diode displays have arrays of display pixels that generate light. In displays of this type, backlighting is not necessary because the display pixels themselves produce light. Other displays contain passive display pixels that can alter the amount of light that is transmitted through the display to display information for a user but do not produce light themselves. As a result, it is often desirable to provide backlight for a display with passive display pixels.
In a typical backlight assembly for a display, a light guide plate is used to distribute backlight generated by a light source such as a light-emitting diode light source. Optical films such as a diffuser layer and brightness enhancing film may be placed on top of the light guide plate. A reflector may be formed under the light guide plate to improve backlight efficiency.
To provide satisfactory backlighting, it may be desirable to locate one or more strips of light-emitting diodes on the edges of a light guide plate. A light strip of light-emitting diodes may be formed by mounting a row of light-emitting diodes onto a flex circuit. Light strips are typically attached at the edges of the light guide plate so that the light-emitting diodes can direct light into the light guide plate.
In an ideal light strip, the light-emitting diodes are aligned with each other so that each light-emitting diode can physically contact the light guide plate. However, there are often placement variations within a row of light-emitting diodes that result in misalignment. If care is not taken, this type of misalignment can result in air gaps between the light-emitting diodes and the light guide plate. The presence of air gaps can have an adverse impact on backlight efficiency. Poor backlight efficiency may in turn decrease power consumption efficiency and can reduce battery life in an electronic device.
It would therefore be desirable to be able to provide electronic devices with improved arrangements for backlighting displays.